Belts for use in continuously variable transmissions (CVTs) such as automobile transmissions, for example, comprise a pair of laminated rings each made up of a plurality of endless ring components of metal that are assembled in a laminated form in their transverse direction. Such a laminated ring is manufactured as follows:
Ring components that serve as respective layers of a laminated ring are produced and stored by a component storage facility. The ring component serving as each layer is basically manufactured such that its circumferential length and radius are of design values (which differ from layer to layer). Generally, however, the actual circumferential lengths and radii of the manufactured ring components suffer errors introduced in the manufacturing process. Therefore, the circumferential lengths and radii of the ring components are not always in exact agreement with design values, but tend to vary from design values to a certain extent. Size data representing the circumferential lengths, radii, etc. of the manufactured ring components are separately measured, and the measured data are stored by association with the individual ring components.
Then, ring components to be used for assembling a laminated ring are selected from the manufactured and stored ring components for use as respective layers, and combined into a laminated ring. Such an assembling process is repeated as many times as the number of required laminated rings.
Since the sizes of the ring components as respective layers suffer variations, when ring components of respective layers are arbitrarily or randomly selected and combined, they may not necessarily make a desired laminated ring. Specifically, a laminated ring for use as a belt in a CVT or the like is required to meet predetermined standard requirements such that the difference between the circumferential lengths or radii of adjacent ring components thereof fall in a certain allowable range. To meet such standard requirements, there are predetermined combinatorial conditions to be satisfied for selecting and combining ring components of respective layers.
The combinatorial conditions include a condition for determining which ring component of which layer is to be selected at first to obtain an individual laminated ring and a condition for determining which ring component of a layer adjacent to a selected ring component of a certain layer is to be selected. Those conditions are predetermined on the basis of the sizes, etc. of ring components. For example, the former condition is determined to select a ring component whose measured data are closest to the design values from those ring components belonging to the radially innermost layer of the laminated ring. For example, the latter condition is determined to select one of two ring components belonging to two adjacent layers, the difference between whose circumferential lengths fall in a predetermined range and is closest to the central value of the predetermined range.
Heretofore, it has been customary for the worker to select and combine ring components of respective layers for a laminated ring by seeing a log of the measured data. Therefore, the conventional process of selecting and combining ring components of respective layers has been tedious and time-consuming.
For increased mass-productivity of laminated rings, it is desirable to obtain as many laminated rings as possible from ring components of respective layers that have been manufactured and stored. However, since combinatorial conditions for combining ring components of respective layers have heretofore been fixedly determined, it has frequently been impossible to obtain as many laminated rings as possible from available ring components of respective layers, tending to leave many ring components unselected and uncombined for use in laminated rings.